Solar cell superfine electrode transfer thin film

ABSTRACT

A solar cell superfine electrode transfer thin film is described. The electrode transfer thin film sequentially includes from bottom to top a substrate, a release layer, a resin layer and a hot melt adhesive layer; the resin layer is formed with electrode trenches therein; the electrode trenches are formed with electrodes therein; superfine conductive electrodes are continuously prepared on a transparent thin film via a roll-to-roll nanoimprinting method, the width of an electrode wire being 2 μm-50 μm, and the width of a typical line being 10 μm-30 μm. Directly attach the superfine electrodes of the hot melt adhesive layer to a solar cell by peeling off the substrate material, and sintering at a high temperature to volatilize the hot melt adhesive layer material while retaining the electrodes, thus the electrodes are integrally transferred, without poor local transfer.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.15/305,748, now U.S. Pat. No. 11,476,373 issued Oct. 18, 2022, which isa U.S. national phase application of PCT/CN2015/075380, which claimspriority to Chinese Patent Application No. 201410265681.4, all of whichare incorporated herein by reference in their entireties.

FIELD

The present disclosure relates to the technical field of solar battery,and in particular to a hyperfine electrode transfer film for a solarbattery, a method for producing the same, and a method for applying thesame.

BACKGROUND

Monocrystalline silicon solar batteries and polysilicon solar batteriesare commonly produced by forming surface electrodes on a silicon surfacewith a process of precise screen printing. Normally, the electrodes havea linewidth of 60 μm to 100 μm. Clogging may occur to the screenprinting with the linewidth of 60 μm due to characteristics of screenand electroconduction slurry, thereby affecting the yield and thequality of electrodes. Further, the electrodes with a large linewidthhas two disadvantages, i.e., large consumption of electroconductionslurry which results in a high cost, and a large coverage for surfaceelectrodes on the silicon chip which affects the photoelectricconversion efficiency of battery. Therefore, it is important to reducethe linewidth of the surface electrodes, decrease the consumption ofelectroconduction slurry and increase the light-receiving area ofbattery.

The production of surface electrodes of solar battery is restricted bythe following factors: compatibility with existing processes of solarbattery, easy implementation, support for efficient processing, acomposite cost lower than the costs for screen printing (including thecosts for the screen and electroconduction slurry), and ease of massproduction of materials.

In a method for producing a front electrode for a solar batterydisclosed in Chinese Patent Application No. 201080023219.3(corresponding to publication no. CN 10244977) which is also a PCTapplication, which is incorporated by reference, an electrode is formedby filling a mold imprinted with a pattern, then is transferred from themold by means of an adhesive film and burned onto a semiconductorsubstrate. The PDMS mold used in the disclosure is soft and therefore isvulnerable, and the electrode has a linewidth above 20 μm, therefore,directly burning the electrode onto the semiconductor substrate willcause problems of production efficiency and environment control.

To address the above issues, it is required to provide a hyperfineelectrode transfer film for a solar battery, a method for producing thesame and a method for applying the same.

SUMMARY

In view of the above, there is provided a hyperfine electrode transferfilm for a solar battery, a method for producing the same, and a methodfor applying the same, so as to solve the problems in the conventionaltechnology.

In order to achieve the above objective, technical solutions accordingto embodiments of the present disclosure are as follows.

A hyperfine electrode transfer film for a solar battery is provided,where the electrode transfer film includes a substrate, a release layer,a resin layer and a hot-melt adhesive layer from bottom to top,electrode trenches are formed in the resin layer, and electrodes areformed in the electrode trenches.

As a further improvement, the electrode trenches and the electrodes havea comb-like structure or a honeycomb structure corresponding to thesolar battery.

As a further improvement, the electrodes are made of a mixed material ofglass microsphere frit and electroconduction slurry.

As a further improvement, the release layer has a thickness of 0.5 μm to1.2 μm, and the hot-melt adhesive layer has a thickness of 0.5 μm to 2.0μm.

As a further improvement, each of the electrode trenches has a linewidthof 2 μm to 50 μm and a depth of 2 μm to 60 μpm.

As a further improvement, each of the electrode trenches has a linewidthof 10 μm to 30 μm.

Accordingly, a method for producing the hyperfine electrode transferfilm for a solar battery includes:

S1, providing the substrate;

S2, applying the release layer on the substrate;

S3, applying the resin layer on the release layer, and forming theelectrode trenches by imprinting on the resin layer with a convex moldcorresponding to an electrode structure, where a linewidth and a depthof each of the electrode trenches are adjusted based on an requirementfor electrode electroconductivity; and

S4, forming the electrodes by filling the electrode trenches withelectroconduction slurry and baking, and applying the hot-melt adhesivelayer on the electrodes.

As a further improvement, the forming the electrodes in step S4includes:

filling the electrode trenches with glass frit and electroconductionslurry, and sintering at a low temperature less than 150 Celsiusdegrees.

As a further improvement, the filling the electrode trenches with glassfrit and electroconduction slurry includes: filling the electrodetrenches with the glass frit and the electroconduction slurry at thesame time; or filling the electrode trenches with the glass frit firstand then with the electroconduction slurry.

Accordingly, a method for applying the hyperfine electrode transfer filmfor a solar battery includes:

attaching the hot-melt adhesive layer of the electrode transfer film toan anti-reflection layer on a surface of the solar battery, and heatingto bond the hot-melt adhesive layer with the anti-reflection layer;

removing the release layer and the substrate to combine the transparentelectrodes on the surface of the solar battery; and

sintering at a high temperature to volatilize the hot-melt adhesivelayer, fuse the electrodes to the surface of the solar battery andcompletely transfer the hyperfine transparent electrodes.

In the present disclosure, roll-to-roll nanoimprinting is adopted,conductive electrodes are produced continuously on a transparent filmand are transferred as a whole, and poor transfer will not occurlocally. Furthermore, the hot-melt adhesive layer and the semiconductorsubstrate are sintered directly at a high temperature, to volatilize thehot-melt adhesive layer and retain the electrodes, thereby achievingreliability, high efficiency and convenience for application.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings required for the description of theembodiments or the conventional technology are described briefly asfollows, so that the technical solutions according to the embodiments ofthe present disclosure or in the conventional technology become clearer.It is apparent that the accompanying drawings in the followingdescription are only some embodiments of the present disclosure. Forthose skilled in the art, other accompanying drawings may be obtainedaccording to these accompanying drawings without any creative work.

FIG. 1 is a structural diagram of an electrode transfer film of thepresent disclosure;

FIG. 2 is a structural diagram of electrodes having a comb-likestructure according to an embodiment of the present disclosure; and

FIG. 3 is a structural diagram of electrodes having a honeycombstructure according to an embodiment of the present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments are described in detail below in conjunction with thecompanying drawings. However, the embodiments are not intended to limitthe disclosure. Any changes of structure, method or function made bythose skilled in the art based on the embodiments fall within theprotection scope of the present disclosure.

A hyperfine electrode transfer film for a solar battery is disclosed.Referring to FIG. 1 , the electrode transfer film includes a substrate10, a release layer 20, a resin layer 30 and a hot-melt adhesive layer40 from bottom to top. Electrode trenches 31 are formed in the resinlayer 30, and electrodes 50 are formed in the electrode trenches 31.

The layers of the disclosure are described as follows.

The substrate 10 normally includes a plastic film or a piece of paper.

The release layer 20 includes a film having a surface separability.Normally, in order to increase a release force of the plastic film orthe paper, the release layer is formed by performing a plasma process ora fluoridization process on the plastic film or the paper, or applying asilicon release agent on a surface of a film material. No stickiness orslight stickiness exists between the release layer and a certainmaterial which are contacted under a limited condition.

In the present disclosure, the release layer is configured to releasethe resin layer 30 and the hot-melt adhesive layer 40 from the substrate10. Preferably, the release layer has a thickness of 0.5 μm to 1.2 μm.

The resin layer 30 is made of UV photosensitive resin. The electrodetrenches 31 are formed by imprinting on the resin layer with a convexmold corresponding to an electrode structure. The electrode trenches 31are configured to grow the electrodes 50. Preferably, each of theelectrode trenches has a linewidth of 2 μm to 50 μm and a depth of 2 μmto 60 μm. Preferably, the electrode trenches have a typical linewidth of10 μm to 30 μm. The electrodes are made of a mixed material of glassfrit and electroconduction slurry. The electrodes are preferably in aform of silver wire, and may be made of metal material in a form of goldwire or copper wire in other embodiments.

Referring to FIGS. 2 and 3 , the electrode trenches 31 and theelectrodes 50 may have a comb-like structure or a honeycomb structurecorrespondingly.

The hot-melt adhesive layer 40 is volatilized after being sintered at ahigh temperature. Preferably, the hot-melt adhesive layer 40 has athickness of 0.5 μm to 2 μm.

A method for producing the hyperfine electrode transfer film for a solarbattery is also provided in the present disclosure. The method includesstep S1 to step S4.

In step S1, the substrate 10 is provided.

In step S2, the release layer 20 having a thickness of 0.5 μm to 1.2 μmis applied on the substrate 10.

In step S3, the resin layer 30 is applied on the release layer 20, andthe electrode trenches 31 are formed by imprinting on the resin layer 30with a convex mold corresponding to an electrode structure. Theelectrode trenches 31 and the electrodes 50 have a comb-like structureor a honeycomb structure. A linewidth and a depth of each of theelectrode trenches are adjusted based on a requirement for electrodeelectroconductivity.

In step S4, the electrodes 50 are formed, by filling the electrodetrenches 31 with electroconduction slurry and baking, and the hot-meltadhesive layer 40 having a thickness of 0.5 μm to 2 μm is applied on theelectrodes.

The electrodes in step S2 are formed by filling the electrode trencheswith the glass frit and the electroconduction slurry through brushing,and sintering (baking) at a low temperature less than 150 Celsiusdegrees.

Furthermore, the glass frit and the electroconduction slurry are filledat the same time, or the glass frit is filled first and then theelectroconduction slurry is filled. Preferably, the percentage of theelectroconduction slurry mass is 80% and may be other percentage of massin other embodiments.

In the present disclosure, a method for applying the hyperfine electrodetransfer film for a solar battery includes the following steps:

attaching the hot-melt adhesive layer of the electrode transfer film toan anti-reflection layer on the surface of the solar battery, andheating to bond the hot-melt adhesive layer with the anti-reflectionlayer;

removing the release layer and the substrate, to combine the transparentelectrodes onto the surface of the solar battery; and

sintering at a high temperature, to volatilize the hot-melt adhesivelayer, fuse the electrodes to the surface of the solar battery, andcompletely transfer the hyperfine transparent electrodes.

For the hyperfine electrode transfer film for a solar battery, themethod for producing the same, and the method for applying the same inthe present disclosure, roll-to-roll nanoimprinting is adopted,conductive electrodes are produced continuously on a transparent filmand are transferred as a whole, and poor transfer will not occurlocally. Furthermore, the hot-melt adhesive layer and the semiconductorsubstrate are sintered directly at a high temperature, to volatilize thehot-melt adhesive layer and retain the electrodes, thereby achievingreliability, high efficiency and convenience for application.

In the present disclosure, the battery includes but is not limited to asolar battery. The solar battery includes but is not limited to anamorphous silicon or microcrystalline silicon film battery, a CIGSbattery, a dye-sensitized solar battery, an organic solar battery, agallium arsenide battery, and the like.

In summary, the technical solutions in the present disclosure have thefollowing advantages over the conventional technology.

The electrodes are produced continuously on a transparent film byroll-to-roll nanoimprinting, the electrodes are transferred as a whole,and poor transfer will not occur locally.

The hot-melt adhesive layer and the semiconductor substrate are sintereddirectly at a high temperature, to volatilize the hot-melt adhesivelayer and retain the electrodes, thereby achieving reliability, highefficiency and convenience for application.

A linewidth less than 30 μm can be realized, and the coverage for theelectrodes on a surface of a silicon chip is reduced by at least 50%.

The electrodes having the honeycomb structure can further reduce thedistance for which a current of the solar battery transmits to theelectrodes, and the carrier recombination rate, and is advantageous forimproving the conversion efficiency.

For those skilled in the art, it is apparent that the present disclosureis not limited to the details in the above exemplary embodiments, butcan be embodied in other forms without departing from the spirit orbasic features of the present disclosure. Therefore, the embodimentsshould be regarded as exemplars rather than limitation in any aspects.The scope of the present disclosure is defined by the appended claimsrather than the above description. All variations within the meaning andscope of equivalents of the claims are included in the presentdisclosure. Any drawing reference in the claims should not be consideredas limitation to a related claim.

Furthermore, it should be understood that the technical solutions in thepresent disclosure are describe with embodiments, but it does not meanthat each embodiment only includes one dependent technical solution. Themanner of description is only for clearness, and those skilled in theart should treat the description as a whole. The technical solutions inthe embodiments can be combined properly to obtain another embodimentunderstandable by those skilled in the art.

We claim:
 1. A hyperfine electrode transfer film for a solar battery,the electrode transfer film comprising: a hot-melt adhesive layer; aresin layer, the resin layer disposed on top of the hot-melt adhesivelayer, the resin layer including electrode trenches formed therein,wherein the resin layer is made of UV photosensitive resin, electrodesare further formed in the electrode trenches already formed in the resinlayer; a substrate; and a release layer disposed on top of the substrateand covering an entire surface of the substrate, wherein the releaselayer is formed by performing a plasma process or a fluoridizationprocess on a plastic film or a paper, or applying a silicon releaseagent on a surface of a film material allowing a surface separability ofthe release layer from the resin layer.
 2. The hyperfine electrodetransfer film as recited in claim 1, wherein the electrode trenches andthe electrodes have a comb-like structure or a honeycomb structurecorresponding to the solar battery.
 3. The hyperfine electrode transferfilm as recited in claim 1, wherein the electrodes are made of a mixedmaterial of glass microsphere frit and electroconduction slurry.
 4. Thehyperfine electrode transfer film as recited in claim 1, wherein therelease layer has a thickness between 0.5 μm and 1.2 μm, and thehot-melt adhesive layer has a thickness between 0.5 μm and 2.0 μm. 5.The hyperfine electrode transfer film as recited in claim 1, whereineach of the electrode trenches has a linewidth between 2 μm and 50 μmand a depth between 2 μm and 60 μm.
 6. The hyperfine electrode transferfilm as recited in claim 5, wherein each of the electrode trenches has alinewidth between 10 μm and 30 μm.
 7. The hyperfine electrode transferfilm as recited in claim 1, wherein the release layer is formed byperforming a plasma process or a fluoridization process on the plasticfilm or the paper, or applying a silicon release agent on a surface of afilm material.
 8. The hyperfine electrode transfer film as recited inclaim 7, wherein there is no stickiness or slight stickiness between therelease layer and the resin layer contacted under a limited condition.9. The hyperfine electrode transfer film as recited in claim 8, whereinthe electrode trenches are formed by imprinting on the resin layer witha convex mold corresponding to an electrode structure, wherein alinewidth and a depth of each of the electrode trenches are adjustedbased on a requirement for electrode electroconductivity.
 10. Thehyperfine electrode transfer film as recited in claim 8, wherein each ofthe electrodes in one of the electrode trenches is filled with a mixedmaterial of glass frit and electroconduction slurry, wherein theelectrodes do not extend to the release layer.
 11. The hyperfineelectrode transfer film as recited in claim 8, wherein the hot-meltadhesive layer is volatilized after being sintered at a hightemperature, to fuse the electrodes to a surface of the solar battery.12. The hyperfine electrode transfer film as recited in claim 11,wherein the hot-melt adhesive layer is attached to an anti-reflectionlayer on a surface of the solar battery.
 13. The hyperfine electrodetransfer film as recited in claim 12, wherein the hot-melt adhesivelayer and the anti-reflection layer are boned via a heating process. 14.The hyperfine electrode transfer film as recited in claim 13, whereinthe hot-melt adhesive layer is sintered at a high temperature to bevolatilized to fuse the electrodes to the surface of the solar battery.15. A method for producing a hyperfine electrode transfer film for asolar battery, the method comprising: providing a substrate; applying arelease layer on the substrate, wherein the release layer covers anentire surface of the substrate, the release layer is formed byperforming a plasma process or a fluoridization process on a plasticfilm, a piece of paper, or applying a silicon release agent on a surfaceof a film material; applying a resin layer on the release layer, theresin layer made of a type of photosensitive resin, and forming aplurality of electrode trenches by imprinting in the resin layer with amold corresponding to an electrode structure, wherein a linewidth or adepth of each of the electrode trenches is adjusted based on arequirement for electrode electroconductivity; growing a plurality ofelectrodes, each of the electrodes in one of the electrode trenches, byfilling the one of the electrode trenches with a mixed material of glassfrit and electroconduction slurry, wherein the electrodes do not extendto the release layer; and applying a hot-melt adhesive layer on theelectrodes, wherein the hot-melt adhesive layer covering an entiresurface of the resin layer is volatilized after being sintered at a hightemperature, to fuse the electrodes to a surface of the solar battery.16. The method according to claim 15, further comprising: attaching thehot-melt adhesive layer to an anti-reflection layer on the surface ofthe solar battery, and heating to bond the hot-melt adhesive layer withthe anti-reflection layer.
 17. The method according to claim 16, furthercomprising: removing the release layer and the substrate; and sinteringat a high temperature to volatilize the hot-melt adhesive layer, fusethe electrodes to the surface of the solar battery.